Slashdot videos: Now with more Slashdot!

View

Discuss

Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).

astroengine writes "The idea of slingshotting a manned spacecraft around Mars isn't a new one. In the 1960's, NASA carried out a feasibility study into an 800-day flyby mission to the Red Planet. And it would have been awesome. AT&T/Bellcomm mathematician A. A. VanderVeen was working for NASA in 1967 and came up with 5 possible launch opportunities between 1978 and 1986 — two windows in 1979 and 1983 provided the shortest transit time between the planets. But launch mass and fuel requirements were a constant issue. So VanderVeen turned to physics to find an elegant, and scientifically exciting, solution: add a Venus flyby to the Mars trip. Mars, Earth, and Venus align with the sun five times every 32 years, but Venus and Mars alignments happen more frequently making double (Earth-Venus-Mars-Earth) or even triple (Earth-Venus-Mars-Venus-Earth) flybys a viable mission. Unfortunately, the flyby never happened."

Short answer: the ISS weighs 495 tons. That's a LOT of mass, and would take a lot of fuel, which itself would take even MORE fuel to get into orbit. A better compromise would probably be something like a small capsule with a habitat module, sort of like the Spacelab [wikipedia.org] module for the shuttle.

Furthermore, the mission profile for a single launch to orbit ejection is much simpler than multiple launches, docking, building a spacecraft in orbit, and then orbit ejection.

What's the advantage to using the ISS as a staging point, as opposed to assembling the vehicle in its own orbital slot? Are you envisioning the ISS acting as on orbit housing for a team of assembly mechanics?

All the plans I've seen so far involve single launches, which dramatically decreases the things a manned vehicle can accomplish on a mission outside Earth's orbit. They have the ISS right there, why not launch three or four modules, strap them together next to the ISS, and then go for Mars with quite a bit more breathing room?

If you have "three or four" modules instead of one, you're also gonna need three or four times the amount of fuel and rocket thrusters, which weighs much more than the modules themselves. In additional to strapping the modules together, you'll also need to strap those thrusters and their fuel tanks together and make them work in a coordinated fashion as one large rocket drive. That's never been done before.

Basically, back in '69, NASA decided on Mars instead of the Shuttle, and everything was sacrificed on the altar of Mars. The NERVA had a horrendous in-flight failure, so they had to go back to chemical, and they chose the Earth-Venus-Mars-Earth trajectory.

Mmmm.. how about to test out technology that hasn't been tried before? That and the fact that landing and boosting off Mars would probably add an order of magnitude of complexity to the project.

As an aside, I was watching a doco on the moon landings recently and they mentioned that the lunar lander on the Apollo 10 mission (which was a full dress rehearsal for Apollo 11 and came with 8 nm of the lunar surface) was not fueled 100% so that Stafford and Cernan wouldn't be tempted to upstage Armstrong by landing on the moon ahead of him.

Mmmm.. how about to test out technology that hasn't been tried before?

Again, there's no real point when you can test it in high orbit instead and be able to return to Earth in a couple of days. You can't test a new engine there easily, but if you're testing a new engine you'd be sending it on an unmanned mission anyway in case it failed.

Mmmm.. how about to test out technology that hasn't been tried before?

That has got to be close the most stupid reason ever.

How about we just build a big vacuume chamber, but the craft in that. Bath the whole thing in radiation for the 800 days. Throw away the key so that everyone dies if anything fails. We are testing the technology right? And it would be cheaper.

A manned fly buy of mars is only slightly more stupid that landing someone on mars. Its cost way more than remote sensor platforms with far more fall out when/if it fails for ZERO gain. Replacing all that life

For most of the world that means 8 nanometers. I had to search Wikipedia to figure it out: "The lowest measured point in the trajectory was 47,400 feet (14.4 km) above the lunar surface at 21:29:43 UTC." (http://en.wikipedia.org/wiki/Apollo_10 [wikipedia.org])

What was the point of a manned ballistic flyby on the moon? Same question, same answer.

APOLLO 8The first manned space craft to leave Earth orbit, reach the Earth's Moon, orbit it and return safely to Earth. The three-astronaut crew — Commander Frank Borman, Command Module Pilot James Lovell, and Lunar Module Pilot William Anders — became the first humans to travel beyond low Earth orbit, the first to see Earth as a whole planet, and then the first to directly see the far side of the Moon.

Yeah but Apollo 10 tested the lander, including the failure mode where they abort a landing and return the ascent stage to orbit. They also tested the lunar surface EVA while in lunar orbut. A flyby won't do any of that.

8 was the Command Module by itself orbiting the moon (20 times). the first humans to go to the moon.

(9 was Command Module and Lunar Module manuevering and docking in Earth Orbit)

10 was the dry run at the moon, doing everything but a full landing, though the LM did descend to within 8.4miles (44,352 feet altitude) of landing on the surface, before launching back into orbit and redocking with the Command Module.

I climb many mountains - for the view. That's the reason I want to be there. I'm not going to climb when there is no view to be had.

Same for going to Mars. You go there to visit Mars - not to have a close-up look, but to really get personal with the planet. If it is just a fly-by, it's like climbing that mountain on a cloudy day: sure you can do it, and if the only point is "because you can do it" then it's fine. But the clouds take away the best part of the climb: the view from up there. Just like a fly-b

The problem with flybys is that they have most of the complexity of a real Mars mission but don't actually achieve much of anything. You have to survive in deep space for a year or more, but all you see of Mars is a fleeting glimpse over the course of a few hours as you zoom past. Venus is even worse, because there's really nothing to see other than clouds.

They made a very limited amount of sense when unmanned spacecraft were really dumb, but they make just about no sense today. At best you'd be testing deep space tech for human spaceflight, but you can test it about as well and much more safely in high Earth orbit.

They made a very limited amount of sense when unmanned spacecraft were really dumb, but they make just about no sense today. At best you'd be testing deep space tech for human spaceflight, but you can test it about as well and much more safely in high Earth orbit.

You are totally correct. How utterly pointless a flyby is.

Im sure doing something for the fact that nobody in human history has ever done it before, being in the history books, the prestige and kudos that comes with it, im sure none of those things have ever had anything to do with human exploration. Im also sure the engineering and science advances that come out of a flyby like this also has nothing to do with it. Nor would be the information gathered from doing 90% of a Mars landing be of any use too.

Nope. Sure, there may be engineering and science advantages to doing a flyby, but it would be relatively pointless. Nobody trains, raises the funds, coordinates the logistics, travels to Everest, and risks their lives for the sake of climbing 90% of the way to the top. Why? Because they can go all the way. Same thing with Mars. We have experience sending probes there. We have experience entering orbit, landing largish payloads softly on the surface. Soon we'll do a sample return mission. When we fi

They made a very limited amount of sense when unmanned spacecraft were really dumb, but they make just about no sense today. At best you'd be testing deep space tech for human spaceflight, but you can test it about as well and much more safely in high Earth orbit.

You are totally correct. How utterly pointless a flyby is.

Im sure doing something for the fact that nobody in human history has ever done it before, being in the history books, the prestige and kudos that comes with it, im sure none of those things have ever had anything to do with human exploration. Im also sure the engineering and science advances that come out of a flyby like this also has nothing to do with it. Nor would be the information gathered from doing 90% of a Mars landing be of any use too.

amiright?

...I'd be willing to bet that most of humanity don't know who Stafford and Cernan are (if you had to look them up to figure out why I mentioned them, I win). The names of Armstrong and Aldrin will be remembered by the average man on the street as long as our species survives.

The names of Armstrong and Aldrin will be remembered by the average man on the street as long as our species survives.

A lot of the current generation don't know who they are. And really why should they? What did they do really? They where part of a billion dollar cold war pissing contest. I blame the apollo program for the current obsession with pointless space tourism for a few "elite" astronauts.

Im also sure the engineering and science advances that come out of a flyby like this also has nothing to do with it. Nor would be the information gathered from doing 90% of a Mars landing be of any use too.

What exactly would you be testing? The manned mission would be using the same rockets we're using on robotic missions- that doesn't need testing. Deep space navigation? Again, robotic missions. Long term life support in space? ISS has been doing that, and if you wanted to work on that as an area of technology then Earth orbit would be a good place to start.

The tricky bits of a proper manned mission are- the landing (a heavy payload that must touch down gently and not pull too many Gs- that's hard), life sup

Im sure doing something for the fact that nobody in human history has ever done it before, being in the history books, the prestige and kudos that comes with it, im sure none of those things have ever had anything to do with human exploration.

Quick, name the crew members of Apollo 8 - the first manned spacecraft not just to fly by the moon, but to leave Earth orbit and the safety of the Van Allen belt.

Drawing a blank? That's ok, you've got two more chances. Name the crew of Apollo 9. Still nothing? H

No. You are not right. Stop being stupid. He didn't say that there was no benefit to a fly-by. He said there would be no benefit to a fly-by OVER testing in space or actually landing on Mars. And a fly-by of Mars is many many times harder than a fly-by of the moon.

Similarly, there would be no point in my trying to commute to work in a city on a horse. Sure, people in history have done great things using horses, and for a long time horses made sense, but today, with the option of driving a car, taking the bu

I never completely understood the need of launching massive ships from Earth whenever we want to leave it. Whenever we wanted to travel the seas, we did not build a massive caravel inland then painstakingly dragged it all the way to the coast. We reasoned it made more sense to build it in a dry dock, that way it only requires a tiny push to get it into the ocean.

Wouldn't anyone at NASA think that making a "Space Dock" made sense?. Make a bunch of tiny trips to lower earth orbit and build the ship there, so you can make a larger ships to travel further. Mass would not be such a big issue (granted, fuel would be), but at least the escape velocity problem would be non-existent.

I never completely understood the need of launching massive ships from Earth whenever we want to leave it. Whenever we wanted to travel the seas, we did not build a massive caravel inland then painstakingly dragged it all the way to the coast. We reasoned it made more sense to build it in a dry dock, that way it only requires a tiny push to get it into the ocean.

I can't tell if you're actually that stupid or if you're pretending to be stupid to make a point. I mean seriously, you can't grasp the difference between a shipyard (dry dock) that you workers can walk to and needs no especial support - and LEO where everything comes with a launch price cost tagged onto it?

Wouldn't anyone at NASA think that making a "Space Dock" made sense?. Make a bunch of tiny trips to lower earth orbit and build the ship there, so you can make a larger ships to travel further. Mass would not be such a big issue (granted, fuel would be), but at least the escape velocity problem would be non-existent.

No, space docks don't make any sense - they don't save you any money, in fact they cost you *more* because of the need to support your assembly on orbit. Mass is still a big issue because you have to pay to boost it. Escape velocity is still a problem, because you still need to boost the fuel to LEO and the mass of your spacecraft beyond LEO.

Yes, eventually we're going to have to face the on-orbit assembly issue, but we're a long way from that. We're still in the 'canoe' phase - which you *can* build inland and carry to the water.

I know this is the internets and being a dick is sort of 'operators license' but that was a rather harsh reply to a question that isn't a bad one.

It's reasonable to ask why we're working on interplanetary manned flights, when one might suggest that it's a better investment of effort (and we gain valuable knowledge about long-term zero-g effects, space construction, and a host of lessons useful to long-duration space trips) to build spacedocks, ie spacecraft construction facilities near Earth.Now, no, LEO is not a solution, but L5 would be.

The first voyage to the new world wasn't in a canoe (well, not on purpose anyway). We made that trip in large, long range vessels, compared to what we were used to sailing at the time.

We're PAST the canoe stage where you could push off from shore but needed to go right back. We've even sailed to and walked around on Iceland, to carry the analogy to its limits. But we won't usefully go further until we're building vessels that aren't an exercise in stuffing 3 dudes into a phone booth (ie Apollo) for days.

And (his fundamental point) is that it's STUPID to loft vessels of that size/scope/capability (or significant pieces thereof) out of our gravity well.

Personally, I see a natural intersection of emerging technologies in autonomous robotics, 3d printing, and (not quite there) mass-drivers pumping raw material from the Lunar surface to an assembly point at L5. Not sure why nobody seems to be talking about it.

I know this is the internets and being a dick is sort of 'operators license' but that was a rather harsh reply to a question that isn't a bad one.

And you're about to get an even harsher one - because you've managed the difficult task of not only being more ignorant on the topic than the OP, but lacking in sufficient reading comprehension, mathematical ability, and simple reasoning ability. You just re-iterate his mistakes (and then add a few of your own), without showing any sign of even trying to comprehe

You're not clever, you're just a dick. Might want to take a dose of Ritalin before you read this reply.

That is, a dick so busy trying to pretend he knows what he's talking about, and so intent on being as offensive as possible (why such gratuitous assholery? Need to prove to mom that despite your basement apartment you are "independent"?) that he can't be bothered to read & comprehend before replying.

1) you're asserting that flying to MARS is easier than developing some sort of space manufacturing - o

The problem is that working in space is hideously expensive. So that the cost of engineering out as much mass as possible to allow you to do everything in a single launch is, bizarrely, cheaper than launching a bunch of heavier-but-simpler-&-cheaper parts to assemble in orbit. For example, right now we can't even launch ship and fuel on separate rockets, which seems a pretty basic skill for a space-faring civilisation.

As we do more in orbit, particularly as private companies actually start operating human-space-flight (even if it's just to provide in-orbit services for NASA/DOD/ESA/JAXA/CSA/etc), we should see techniques developed to make operations in space cheaper. At some point we'll reach the cross over where assembly is always cheaper than single-launch. After that, someone will inevitably start building a "space-dock".

It's like reusable launchers. Logically, using a launch vehicle 100 times should be cheaper than using it once and throwing it away; look at aircraft, who would build a single-use plane? But so far we haven't been able to figure out how to make refurbishable craft cheaper than disposable ones.

So that the cost of engineering out as much mass as possible to allow you to do everything in a single launch is, bizarrely, cheaper than launching a bunch of heavier-but-simpler-&-cheaper parts to assemble in orbit.

Generally cost scales only weakly with mass, but scales very strongly with complexity. The real cost of objects on orbit isn't the heavy parts - it's all the lightweight parts (all the parts that actually do the work) and all the interconnections between them. The thing is, those lightwei

I never completely understood the need of launching massive ships from Earth whenever we want to leave it. Whenever we wanted to travel the seas, we did not build a massive caravel inland then painstakingly dragged it all the way to the coast. We reasoned it made more sense to build it in a dry dock, that way it only requires a tiny push to get it into the ocean.

Wouldn't anyone at NASA think that making a "Space Dock" made sense?. Make a bunch of tiny trips to lower earth orbit and build the ship there, so you can make a larger ships to travel further. Mass would not be such a big issue (granted, fuel would be), but at least the escape velocity problem would be non-existent.

Well, national space programs are not about exploring new frontiers. Military superiority and a corporate welfare program for defense contractors are about the only reasons that nation-states even pretend to have a "space program." NB: I'm not disagreeing with you -- if the US wanted a space program for exploration, that's what they should be doing, and as a tax-payer, I would be bitching loudly if they weren't. But exploration is not what the space program is for, so I don't bitch about it very much at

If they're not going to actually land, what exactly is the point of manning it? To reduce the couple minute delay on controls by having a human on location? Well, a robot can stay there for years so time isn't a real big thing unless everyone's just that impatient.

All talks of "manned flight to Mars" centered around getting living human beings into a little confined spaced for hundreds of days

Even if every single thing works out - no one die on route, no accident, no nothing - it would still be an extremely cramped up place for human beings, and the psychological trauma of cooped up inside a holding cell for hundreds of days isn't something easy to deal with

If you look back in history, few real voyages of exploration had an 'escape plan'. If you're not willing to lose a few crews, you shouldn't be sending them out there.

Bingo. The entirety of human evolution, biologically and technologically, has been driven by trying something and not dying from it. As a result, we've made tremendous progress both is achieving stated goals and in escaping from failure. Everyone trying something new should expect that death is always a possibility, despite the remarkable efforts to reduce its chance.

Space exploration is to sea exploration like... well, like hard vacuum is to getting stranded on a beach:

There's (forgive the pun) astronomically less chance of surviving a fuckup in space.

Not a fair comparison. What you should have said is along the lines of Space exploration is to sea exploration like a hard vacuum is to many hundreds or thousands of PSI of water pressure crushing you. Either way, you're stuffed if something serious goes wrong.

Also worth bearing in mind: While the great unexplored destinations of the age of sail were far more forgiving than our neighbour planets, the technology and the level of human organisation was not.

- The people back then built amazing ships, but their construction methods were based on rule of thumb craftsmanship rather than highly-specced precision engineering.- Ditto for materials. They had no ISO reassurance that a given beam of wood would stand up to the forces and stresses of a storm.- Their crews were

From a human perspective, it's just as terrifying. Fear of sea monsters, pirates, doldrums, and gods' anger contributed to early sailors' supposedly-known risks, yet they still went exploring. Eventually we learned that there are no sea monsters or vengeful gods, but that doesn't diminish the courage of those who faced the risk willingly. Likewise, we know that hard vacuum will kill us, but there are still those brave enough to face such a danger willingly fo

It would have been an incredibly uncomfortable journey in 70s or 80's with the equipment on hand at that time.They were thinking of using Apollo hardware. That didn't necessarily have to be mean JUST the capsule, because Skylab was a concurrent project, and it too was built out of the Apollo project in its early eays. Skylab was launched 14 May 1973, and it could have served as living space for a longer Mars mission.

A Mars ship with the capacity of Skylab for a 3 or 4 person crew would seem the ideal way to travel compared anything else that has been proposed. The Saturn 3rd stage provided a volume of a small townhome with large area the crew could even 'run' in. Probably the closest thing that could be managed today would be a few Bigelow modules to provide a bit of elbow room to a crew.

Food storage is indeed a problem. 800 days is just beyond the outer limits of what can be done with current freeze-dry technology

Why not just choose a crew from the long list of regular volunteers you will have applying for every flight? Including, I suspect, every single currently trained astronaut and astronaut candidate in the world. And a hell of a lot of former ones. I don't know why this "Send criminals" meme keeps being passed around.